Flip decision depends on the height of your room and light, what kind of lights you are using, what kind of support setup you use for branch support, and some other factors..........you will see some variation in plants height, expect about 1/4 of them to really stretch. So 90% of the plants will stretch between 2X-3X. Instead of pinching, you can also bend the main stalk downward, which will disperse the plants hormones, and will shorten and widen the plants too. Find my thread, everything you could possible want to know is probably in there.